27.15.1.3. packaging.version — Version number classes

This module contains classes and functions useful to deal with version numbers. It’s an implementation of version specifiers as defined in PEP 345.

27.15.1.3.1. Version numbers

class packaging.version.NormalizedVersion(self, s, error_on_huge_major_num=True)

A specific version of a distribution, as described in PEP 345. s is a string object containing the version number (for example '1.2b1'), error_on_huge_major_num a boolean specifying whether to consider an apparent use of a year or full date as the major version number an error.

The rationale for the second argument is that there were projects using years or full dates as version numbers, which could cause problems with some packaging systems sorting.

Instances of this class can be compared and sorted:

>>> NormalizedVersion('1.2b1') < NormalizedVersion('1.2')
True

NormalizedVersion is used internally by VersionPredicate to do its work.

class packaging.version.IrrationalVersionError

Exception raised when an invalid string is given to NormalizedVersion.

>>> NormalizedVersion("irrational_version_number")
...
IrrationalVersionError: irrational_version_number

packaging.version.suggest_normalized_version(s)

Before standardization in PEP 386, various schemes were in use. Packaging provides a function to try to convert any string to a valid, normalized version:

>>> suggest_normalized_version('2.1-rc1')
2.1c1

If suggest_normalized_version() can’t make sense of the given string, it will return None:

>>> print(suggest_normalized_version('not a version'))
None

27.15.1.3.2. Version predicates

class packaging.version.VersionPredicate(predicate)

This class deals with the parsing of field values like ProjectName (>=version).

match(version)

Test if a version number matches the predicate:

>>> version = VersionPredicate("ProjectName (<1.2, >1.0)")
>>> version.match("1.2.1")
False
>>> version.match("1.1.1")
True

27.15.1.3.3. Validation helpers

If you want to use LBYL-style checks instead of instantiating the classes and catching IrrationalVersionError and ValueError, you can use these functions:

packaging.version.is_valid_version(predicate)

Check whether the given string is a valid version number. Example of valid strings: '1.2', '4.2.0.dev4', '2.5.4.post2'.

packaging.version.is_valid_versions(predicate)

Check whether the given string is a valid value for specifying multiple versions, such as in the Requires-Python field. Example: '2.7, >=3.2'.

packaging.version.is_valid_predicate(predicate)

Check whether the given string is a valid version predicate. Examples: 'some.project == 4.5, <= 4.7', 'speciallib (> 1.0, != 1.4.2, < 2.0)'.